Added validation for folder names. Fixes #404

Modules/Media/Http/Requests/CreateFolderRequest.php

@@ -13,6 +13,7 @@ class CreateFolderRequest extends FormRequest
 
         return [
             'name' => [
+                'alpha_dash',
                 'required',
                 Rule::unique('media__files', 'filename')->where(function ($query) use ($parentId) {
                     return $query->where('is_folder', 1)->where('folder_id', $parentId);